


Police Sirens

by old_shizuumi151 (shizuumi151)



Category: Free!
Genre: M/M
Language: English
Status: In-Progress
Published: 2015-01-18
Updated: 2015-01-30
Packaged: 2018-03-08 02:27:03
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 7,010
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3191846
Author URL: https://archiveofourown.org/users/shizuumi151/pseuds/old_shizuumi151
Summary: <blockquote class="userstuff">
              <p>Another future fish AU where Rin's a cop and Haru's a mermaid.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> before anything just know that i can't title gay shit to save my life

The cloudless sky graduated from baby blues to petal pinks, complementing the burning half-sun spilling its rays across the stretching sea. Waves crept along the beach, darkening the sand shy of where Rin’s footsteps crunched, growing louder with his approach like the his breaths puffing out of his lungs or the sea foam growling on the shoreline.

It was a Saturday evening, which meant he was off-duty. He could go for his seaside jog instead of clocking in at the station for another day of patrol and paperwork. He could run along the wake of dying waves at the leisure of having a few extra hours of sleep, and subconsciously relishing the gentle heat of what was left of the sunset, the subdued whispers of the wide, wide sea, and nothing else except the rush of blood through his muscles, to pump him further to hone his body, nothing else, nothing…else…

 

…Nothing…

 

_Can you hear me_

 

…Funny. Rin…hadn’t brought any music. Yet…a wash of song seeped into his ears, numbing his mind, and…

 

_If you hear me_

_Come to me_

 

The last intelligent thought that passed through his brain was: ‘ _That voice sounds fucking majesti—_ ’

 

 

_Come_

 

 

His vision blurred.

The sharp red of his eyes dulled as they glazed over, but he didn’t faint. He felt so heavy, so, so…heavy…but his legs dragged along the sand, still, to that…music. That _voice_. It was by the rocks,

by the rocks,

by the rocks,

by the r o c k s —

 

_Here_

 

The sweat on his skin had cooled, but it wasn’t unpleasant, because he couldn’t feel his skin beyond the buzz of the song.

 

_I’m right here_

 

Dimly, Rin might’ve realised he would thoroughly ruin his trainers stepping closer to the surf, to the nest of rocks where the source of the voice laid behind. He didn’t care though, because what little energy he had left was fuelled by the chant, the song. It felt soothing, empowering, _enchanting_.

 

_You’re so close_

_You’re almost here_

 

He clumsily manoeuvred around the dark, soaked rocks at the chant growing louder with the closing, tantalising distance. His arms were dead weights, dragging him down to the sandy earth, but he plodded on in a daze, to find _where_ that song was _coming_ from—

 

_Yes_

 

His sight blurred at the edges like a vignette, but what he saw still communicated to his increasingly untethered mind.

A man lying on the surf.

 

_You found me_

 

He wasn’t speaking, but sounds and song drew out of this man’s long, smooth throat. This man, who was nude, soaked to the bone, whose skin…Could a man’s skin shimmer and glow? Could a man’s hair be that inky and sweeping? Could a man’s thick, low lashes — oceanic scent — rich, _rich_ voice trap him, trap him—trap him, —— t r a p …

 

_I’m waiting_

 

Rin’s footing stuttered as he continued, walking towards the call.

All he could see was the man’s chilling eyes, all he could do was drown in his scent, his glow, his light, his _touch_ —

 

_Now,_

_Come_

 

His hand was so cold, pale, and wet on Rin’s cheek, but his mouth — it seemed so pink and open and close, this, must’ve, been —

 

 

**Closer**

 

 

 

_-— R — r — **ngh** —!_

 

A hiss shattered his vision.

 

Rin lurched forward. He gasped at the intense rush of clarity, of the sobering sensation of his consciousness being thrown back into his clattering skull. Slowly, he registered that he was panting deeply. His hands were lodged in the wet sand for support.

He blinked once, and his breath shuddered.

He blinked again, and saw between his arms someone writhing beneath him.

“Wha…“ Rin exhaled. His gaze fell to the man splayed beneath him, to the cold hand still on his own cheek. He gulped dryly. ”H-Hey, you—are you alright…?”

 

He froze at the sight of scales.

 

Iridescent, hard scales littered the man’s pale skin, on his defined arms and bare torso. And gills — open, parallel cuts on his long, slim neck fluttered in time with his small, gasping lips. His icy fingertips fell from Rin’s cheek, so that long, blue fingernails could be seen.

Rin’s eyes darted at an increasingly frantic pace. His heart—that had pumped a bone-rattling, merciless adrenaline—had skipped a beat when he looked down.

The man’s tail flinched.

 

_Siren._

 

“What the—” Rin swallowed, his nauseating confusion quickly extinguished at the tail thrashing underneath. Currant red blood oozed from a yawning gash, marring the slippery flesh where shins would’ve been. “Holy shit, did I—” He looked back up, just when the creature roused, unscrewing their eyes. “Hey, hey, what happened to— _crap_ , can—can you understand me—?”

When they opened their eyes, Rin had to stop.

They still panted lightly, their cheekbones suffused with an unseemly flush, their winsome features delicately scrunched in what had to be pain, what had to be agony, but

what bright, _blue_ eyes.

“ _Oh my fuck_ …”

For a moment, Rin was entirely arrested, struck dumb by this creature’s sheer perfection. Then he realised they were trying to make noise, their mouth trembling with wispy vowels.

“Wh-What is it?”

“…Ah, ah—” their eyes searched over Rin, trying for understanding as their jaw tightened. “— _Ahn_ …”

Rin willed away the heat in his face, hastily readjusting his focus on the siren's meaning than the breathlessness of their gasps. He squinted, gritting his teeth because they  _wanted_ something, but to no avail.

“I…I can’t,” Rin shook his head, conscience-stricken. “I can’t understand you, but,” he looked down at the blood smeared on his own legs, and some that spilled onto the sand. “I’m going to get you to my place, so I can bandage that up—” he cursed, bringing his focus back to them so he could gesture out _something_ , instead of—

“Hngh!”

Rin’s mouth fell a hair open at their wrought expression, at the sensation of both, chilled palms grasping his slack jaw. Cold, webbed fingers fisted into his hair.

“Hey, what’re you—mn— _mhhn_ —?!”

Their arms tightened, and their lips mashed in a desperate pull.

Rin collapsed onto his elbows, eyes blown painfully wide. The siren's were pinched shut, as their hot, wet mouth shifted against Rin’s tight. Heat started and gushed through his insides; the creature’s all too sensual, human lips desperately tried to coax an opening. He jolted at their teeth nipping his swelling, pulsing lips, and his mouth shivered open in a weak moan. They wasted no time dipping in their tongue, making the warm, electrifying sensation course down his spine, but Rin wrenched away before it laved his sharp teeth.

“Wh—” his hands were on their shoulders, pushing it down and away as his breaths came hot and ragged. His running clothes were now dripping with sea water, and the sides of his leg with blood. The creature growled in irritation, their drying skin wrestling out of Rin’s hands, before Rin started yelling. “ _What the hell d’you think you’re—_?!”

“ **No** …” their voice came thick, stuttered. Rin was momentarily stunned–by the siren's newfound vocabulary, by their strained glare and blazing eyes before he was pulled again. “ **Back**.”

They shot an arm around his neck, seizing his bicep before plunging his tongue in the depths of Rin’s mouth.

“Hn— _nh_ …!” He broke away with a startled gasp, but they followed the backwards knock of his head to capture his lips once more, tongue slithering between again.

His eyes watered from squeezing so hard, his strength sapping with every mind-numbing coil of their tongue pressing his hard palate, lining his pointed teeth, licking the slipperiness under his own. His mouth and body burned with the fleshly pleasure, tuning out the chunky sand and cool sea winds, as the beginnings of their slick tail squirmed against his pants, grinding against his throbbing, rousing cock.

“Pah—” Rin jerked his head aside, coughing back his breath just as it tipped him over onto his back. “— _Mph_!”

He shivered at their cool teeth eagerly nibbling his puffing lips, slick with saliva, their tongue tracing the flesh of his mouth more gently than before.

 

Then they suckled his bottom lip between their teeth, and bit down.

 

“ _Yeow_ —!!” Rin manage to back away from the shock of the bite, and this time the siren didn’t follow him. He registered a crimson smear on their slightly darkened lips, before he brought his fingers to his own to confirm that it _had_ drawn blood. He breathed hard and heavy, lungs fighting to regain air before he choked on his indignation. “ _Shit_ , what the fuck was that for?!”

 

“Communication.”

 

Rin’s eyes bulged. He whipped his head up after hearing their clear, fluent Japanese. If it weren’t for the subtle colour on their cheeks, the creature would’ve looked completely unaffected, as if they hadn’t engaged the most intense, one-sided make-out session that Rin had ever experienced in his short life.

He started to sit up, watching the shadowed face of the siren on top of him. “…Huh?”

“It was necessary—” they winced, and started to lose balance. “I need you…to…”

“ _Whoa_!” Rin caught the siren on reflex before they rumpled to the sand, hastily sitting up so he could cradle it better. “Easy there. You’re injured…” he murmured, glancing at blood surging from their wound anew.

Their breath shuddered, chest quaking in Rin’s hold, hand grasping the front of his running jacket. And despite all their cunning and aggression, Rin’s chest still knotted at how it grew paler by the second.

“I just need…seaweed,” they rasped, grip losing purchase on Rin’s chest. “Then I can…help…myse…”

“I’m gonna put pressure on it,” Rin mumbled, carefully but quickly unzipping his jacket while keeping them upright. “Just stay with me. What’s your name?”

“Name…?” they whispered, swallowing weakly as Rin wrapped his jacket around their tail. “…Haruka…”

Rin didn’t look away from addressing the wound, but his brows rose. “Japanese?”

“It’s the closest translation— _ngh_!”

“Yeah, s’gonna hurt,” Rin clicked his tongue, but his makeshift dressing was complete. “I got a first-aid kit back at my place, so I’ll have to take you in.” His eyes narrowed at Haruka’s scoff. “What’s so funny?”

“Irony,” they explained tersely, a tease at the corner of his lip. “A siren at a human’s mercy.”

“I’ll bet that’s a riot,” Rin snarked. He kneeled beside Haruka, and wriggled his hands underneath their body. He frowned. “You’re kinda dry. Isn’t that bad?”

“I…can be dry for some time,” Haruka said, pliant as they were heaved into Rin’s arms. “…You are strange.”

“Hm?” Rin stood quite easily. It was evening now, and his eyes adjusted to the moon’s dim rays as his feet dug into the wet sand, back to the pavement leading home. “What is it?”

“You…” Haruka fell quiet. Their words slurred as his damp head of hair fell to Rin’s chest. “Are not frightened.”

Rin smiled despite himself, at how demure they sounded.

“And why would I be?”

“…I frighten people.”

“Sorry to disappoint, but I don’t scare easily,” he quipped. “…Though now that I think about it, the fact that you were trying to lure me for dinner then making out with me was kinda creepy. Like that Teen Titans shit.” Haruka tensed, and he rolled his eyes. “Yeah, we humans know what sirens are.”

“I apologise.”

“ _Pffft_ ,” Rin pursed his lips to suppress his chuckles, but they burst loose all the same. “What sorta siren _apologises_?”

Haruka pouted, tucking his head in. “What sort of human lets a siren enter their abode?”

“Huh, so you _do_ gotta mouth on ya,” he grinned, heading for the entranceway to the pavement. “Well, first, you’re at my mercy, so I’m figuring we can make this a two-way street and have me feed you some fish and you not eat me alive. Second, not that I wanted it to happen or anything, but I thought you’d pass out by now.”

“It is…more complicated than this, but,” Haruka sighed. “I am out of water, so I am conserving my body fluids, so the bleeding is less.”

“Gotcha,” Rin whistled, not at all fazed by Haruka’s stiff wording. A reaction that irritated them.

“…Other humans might see me.”

“Nah. This time of day and this kind of weather? No one comes to this part of town.”

“Your arms will be weak after carrying me for so long.”

“I work out.”

“I might be faking weakness.”

“Yeah, not with a big-ass cut you aren’t.”

“I…I…” Haruka paused in thought, before frowning up at Rin. “You are an annoying human.”

He smirked. “Why thanks, siren-at-my-mercy.”

“I am being serious,” Haruka said, their serious tone unfortunately sounding very child-like and endearing. “I cannot understand why you are helping me.”

Rin didn’t answer for a few metres, quietly walking under two to three sodium lamps that illuminated the path.

“I s’pose…” he looked down at Haruka. An easy, spirited grin revealed his fascinating, pointed teeth. “I always wanted to meet a mermaid!”

Haruka blinked. A strange, warm sensation seemed to hold their chest.

“…I am a _siren_.”

“Same difference.”

**Notes for the Chapter:**

> edit: i corrected all of haruka's pronouns :)


	2. Chapter 2

**Summary for the Chapter:**

> The officer and the siren reach the apartment

“I realise that I do not know your name,” Haruka noticed as they waited outside a door. They watched their carrier mumble and search through what Haruka knew as shorts. “Do you have one?”

He grunted, still digging through his pockets while cradling the weighty siren. “Yeah, my name’s Rin—fucking _Christ_ , where the hell is it...?”

“I see,” they heard a slight jingling, and spotted Rin holding metal things. Keys. “Do you have any shorter name than Rinfuckingchrist, though?”

“Wha— _no_ , shit, that’s not—!” Rin nearly doubled over in a laugh, a reckless sound that was too loud to Haruka’s ears. “My name’s just _Rin_. Matsuoka Rin.”

They tilted their head. “If it is just Rin, then what is Matsuoka?”

“It’s a surna—ah, forget it,” Rin kept his focus on the doorknob, and his keys clicked inside. “Just call me Rin, okay?”

Haruka shrugged, coming to accept that Rin would be a confusing human. “Alright, Rin.”

“Good. And…” Rin bit his tongue, juggling his focus between jiggling the key in his doorknob and keeping Haruka close with one arm. “… _There_!”

Haruka kept watching impassively as it hung onto Rin’s neck. Coral blue eyes widened a touch, critical as they watched the covered end of his limb—his foot—nudge open the door. The abode—or apartment, rather—that the strange, simple human had led them to.

Even in the darkened room, their eyes could distinguish objects that he could now effortlessly name in this human’s tongue. Mysterious contraptions and fixtures became somewhat known: a television, a computer, a balcony. Such was the power of their acquisition, to be able to recognise and label like they were native.

 

In a click, the room burst into light.

 

“ _Rgh_ —!” Haruka gave a strangled hiss; their arm shot up to protect their eyes from searing colour. “ ** _Bright…!_** ”

“Oh, shit,” his head snapped to Haruka’s recoil, arms squeezing on reflex after he’d switched on the lights. “You’re probably used to the dark—your eyes okay?”

“They…are fine,” they grumbled slowly, their head timidly turning as it blinked tentatively. They could see peculiar, translucent traces of purple, but their eyes adjusted to the brightness. “I have not gone blind.”

Rin couldn’t help his snicker. “Good t’hear.”

“Your…apartment,” Haruka muttered, letting the new word brush past their lips. It looked warm from the light, akin to how yellow light dapples across the water at sunrise. They looked over the foreign things taking up space—furniture—before their nose scrunched in distaste. “It has no water.”

“Nah, it does, just not so much in the living room.” Rin responded easily, lightly bouncing Haruka up to readjust his grip. “How much longer can you go without it?”

“I…” Haruka paused, their mind processing the parameters that humans restrained time with. “…Hours. A few hours.”

“Shit, that’s a relief; I don’t have a bathtub here,” Rin sighed, clicking his tongue as he looked for a solution anyway.

“Bathtub…” Haruka murmured, and an image of a glossy white tub sprung to mind. It was another feature of their acquisition, but Haruka still frowned in digesting the abnormal reality of such a confining object.

Rin’s body pivoted around as he looked around the room, making Haruka’s tail idly swing to his turns. There were cream walls, red beanbags and sofas, and sleek black tables—it was Rin’s ideal bachelor pad, but didn’t offer much accommodation for an injured siren.

“Wait—I _think_ I got a blow-up pool in the storeroom…” he recalled, pondering.

His lips pulled in thought, and he looked down at Haruka’s relaxed deadpan.

“Yes, Rin?”

“I’m…gonna treat your wound first, then set you in some water,“ he decided, talking more to himself than the siren blinking up at him. ”Wait, actually—would it work if I give you a drink of water from time to time?"

“That should work…” Haruka murmured, studying Rin’s face. “If I am hydrated, I will be healthy.”

“Okay, great, um,” Rin glanced back around to his kitchen. “I’ll just—put you down on this here, and get you a glass before I fix you up,” he quickly explained, already lowering onto his knees to set Haruka down. Their jet hair gradually unstuck from his collarbone, and his arms relaxed as their weight gently sunk into the plushness of the beanbag.

“Ah—”

“Easy…easy…there,” Rin let out a triumphant puff. His arms were akimbo as he kneeled, taking in how the cushion slightly swallowed Haruka’s lithe body.

“This is…velvet?” Haruka’s eyes widened a fraction, gleaming at the foreign texture.

“Yup, it’s a velvet beanbag,” Rin beamed. “Feels nice, doesn’t it?”

They shuffled themself deeper into the cushion, humming. “Yes…”

Rin allowed the relief of their comfort to wash over him, so he decided to take pause. He stayed kneeling for a few moments, to take in the reality of Haruka the siren lounging on his favourite beanbag.

He studied how the planes of their chest rose and fell, and how their gills pulsed in time with their small breaths. Opaline blue scales scattered over their flawless skin, scales which covered their smooth, thick tail. The dark splotches lining the wound suppressed by his creasing jacket twisted at Rin’s heart, yet his vision still trailed down the gossamer of their tail fins.

 

And against all his better judgement, Rin gazed upon Haruka’s face again.

 

Their features didn’t look particularly masculine or feminine, despite the male build of their chest, but there was a beautiful perfection in their androgyny. They had a faultless complexion and soft yet defined features. Their lashes were dark and long over their cheekbones; their eyes were upturned, round, a clear, _dazzling_ blue…

…and staring right at him.

 

Rin’s mouth flapped intelligently. “…Uh…”

They stared at each other through the silence. Haruka’s silent gaze pierced with its strength, and Rin’s cheeks grew palpably warm.

“Are you going to treat my injury?”

 

Their rich, smooth voice left him tongue-tied.

 

“U-Um, yeah…I was just gonna—I mean,” he clapped his thighs, rubbing them hard as his lips pursed in a fluster. “I am, s’just—I just got— _distracted_ , a bit, I…” Haruka watched him kneel, captivated again by his peculiar behaviour. “Sorry, you’re hurt, I should—I’ll get you a water—I mean some cup— _I mean_ —!” he coughed. Their neck craned up when he shot to his feet. “…Water.”

Haruka cocked their head in intrigue as he stomped away.

 

“How odd…”

 

Their wound pulsed dully, and their head laid back into the soft beanbag. They closed their eyes to the faint sound of a squeak, of rushing water from the kitchen.

“Kitchen…where humans…make food.” They looked around Rin’s apartment, searching for more things they could name with their newly acquired tongue. “Walls…ceiling…knick-knacks…coffee table…painting…picture frame—”

They stopped at seeing the content within. Unknown humans were baring their teeth—smiling—while packed together to fit in the frame. Haruka knew it was a photograph, but they wondered how it was possible—how could humans capture others in such a way?

There was a young human on the left, whose hair was bundled at the top of its head. Its face was small and its body seemed soft under their clothing; its eyes and hair were red.

The word ‘ _woman_ ’ entered Haruka’s mind, but they weren’t quite sure what that meant.

In the middle was a much bigger human, whose body seemed broader and sharper than the woman’s. This one’s hair was short, spiky, and a very deep brown. Its eyes were downturned and blue-green. It looked formidable, but their smile seemed harmless.

The word ‘ _man_ ’ flashed in Haruka’s brain, but they weren’t entirely sure what that meant either. It looked at the woman and man again with unfamiliarity.

“Strangers…”

Their focus slid to the right of the photograph, where there was another broad-shouldered human. Messy red locks framed a beaming face, and their teeth resembled those of a baby shark.

Against their sensibility, Haruka’s eyes lit up in recognition.

 

“—Rin.”

 

* * *

 

“Now, this is disinfectant,” Rin jammed the bottle with a cotton ball, and watched it carefully as it soaked. “This is gonna hurt a bit—”

“—If you misuse the expression ‘ _a bit_ ’ again, I will eat you alive," Haruka hissed, the strained flush of their cheeks dampening their menace.

“Now, now,” Rin’s eyes thinned with amusement as he put the bottle back upright. “Is that any way to talk to someone helping you out of the _goodness_ of their _heart_?”

“Do not mock my pain,” they warned, but helplessly watched Rin pin down his tail and ready the damp cotton. “Are you…sure this is needed— _agh_!!”

The cotton pressed and burned their wound. Their tail jolted under Rin’s vice grip, and a wail ripped out of Haruka’s throat.

“This is first time you’ve went through this, isn’t it…” he remarked in sympathy, grunting as he made sure Haruka’s thrashing didn’t throw him off. “I saw how this cut oozed; you need this,” he murmured, retracting his hand when the cotton soaked with red and yellow. “Just once more and I’ll dress it up. It’ll be over soon.”

Haruka panted in the sweeping relief, their breath hoarse as they pushed their weighing body up on their elbows. “Do not…pity me… _either_ …”

“What’d you like me to do then?” Rin asked with a raised brow, the dry question coming out soft as he focused on soaking another clean cotton ball. “Watch the cut fester and then see your tail amputated?”

The blush drained from Haruka’s face. “Ampu…tated…?”

“Mhm,” Rin hummed, nodding with a grave pout. “You know what that means, right?”

“Yes…” they swallowed, and eyed Rin rummaging for something in his kit. “I do.”

“Great,” a gentle smile played on his lips, and he handed Haruka a clean towel. “Bite this. Dunno if it’ll help the pain so much, but you won’t scream out.”

The strange sensation returned, swirling in Haruka’s chest at the human’s eyes. Bright, like something Haruka had only ever heard of in fables and folk tales of land above the seas. The stuff the suns and stars were made of.

 

_…Fire…_

 

They snatched the cloth out of Rin’s hands.

“Just hurry,” Haruka muttered. Rin’s brow rose again, and their eyes darted aside. “…Please.”

His lips curved in a warm grin. “Roger that.”

* * *

“Do all humans have ‘kiddie pools’?” Haruka asked, timid yet avid in their examination of the pink, plastic pool in the living room. “Can they not just go to the sea?”

“Not all of ’em, no. And some people might not live near the sea enough to swim in it,” Rin answered, and kept working on fattening the pool. It was even decorated with unrealistically pleasant red sharks, which slowly started to grow bigger and shinier with air.

Haruka rolled around on their beanbag for a better angle, ending up looking at the pool and the human upside down, their arms spread eagle. Their fringe, now dry and soft, fell to show their smooth forehead, making their curious eyes look wider and brighter.

 

“…Why are there drawings of sharks on your pool?”

“’Cause I like ’em,“ he shrugged, hands lax in pockets as his leg worked the foot pump. ”Sharks are cool."

Haruka nodded. “They are cold-blooded, yes.”

“Ah, no, I meant like—they’re impressive, to me.”

“Ah.”

“Yeah…”

 

Air hissed and leaked with every press of Rin’s foot, and filled the gentle silence. In the stretch of quiet, Haruka rolled into their stomach, which also enjoyed the dry, fluffy texture. Their bandaged tail bent upwards, not unlike how a human bent their knees, and swayed lazily like a stalk of wheat in a gentle wind.

 

“…It is easy to make sure they cannot swim anymore,” Haruka spoke up, their cheek indulging in the supple cushion. “They are vulnerable.”

“Yeah, flip ’em upside down. Tonic immobility,” Rin nodded. Bright blue eyes blinked, and he smirked in response. "Yeah, we humans got a name for most things.”

There was an unmistakable pride in his voice. Realising that Rin must have sensed their surprise, Haruka immediately schooled their features.

“…I see.”

Haruka frowned. They ensured their tone was composed, yet Rin still snorted under his breath.

 

_What a rude human._

 

* * *

“Where are you getting all this water from?”

Haruka furrowed their slim brows, beyond perplexed as Rin kept entering and leaving the room with a metal container. Even though the pool was almost full, Haruka’s attention was firmly grasped by the weirdness of this phenomenon.

“From the tap,” Rin poured another bucketful of cool water in the pool. “Know what that is?”

“Yes, but—” Haruka pouted, having to wait for Rin disappearing into a hallway with an empty bucket, then reappearing with it mystically full. “I still do not understand. Explain to me. Please."

“Humans collect and clean a lot of water, which they store in a reservoir or a factory, I’m pretty sure,” Rin began to explain, the words registering with Haruka’s imagination as he carefully tipped in the last bucketful. “Then there’s a bunch of pipes that connect taps to those water supplies.”

“So…that is how you can load this pool you filled?”

“Technically I pumped the pool and now I’ve filled it,” Rin corrected, wiping some sweat off his brow in a huff. “But yeah, that’s how I can do it. I’ll just put you here, then it should be good…”

“Ah,” Haruka looked down, contemplating before they looked up again. "You are good at pumping and filling.”

“I’m gonna ignore that…” Rin mumbled, hoping his cheeks weren’t as red as they felt. He moved closer to Haruka, whose brows drew in a petulant stare as he lowered himself on one knee.

“Why would you ignore my compliment?” they asked, ever bemused.

“Nothin’ that you need to worry about…” Rin bit the tip of his tongue, and shimmied his arms under their smooth back and tail. “Now, up you… _go_!”

He promptly rolled Haruka into the crooks of his elbows. They naturally slung their arms around his neck again, and felt the heaviness of land disappear when they were lifted up.

“I am heavy,” Haruka noted, their focus back on Rin’s face as the closest object in their vision. “Yet you look relaxed.”

“Why wouldn’t I be?” Rin asked, baring teeth. “You’re light as a feather.”

Haruka imagined the feathers of airborne gulls, and lowered a brow. “I am much heavier than a feather.”

“Figure of speech,” Rin shrugged, and he started to kneel again when beside the waiting pool. “This is alright, yeah?”

Haruka blinked at his expectant expression. Looking to the calling water, they dipped in the tips of their fins, rippling the familiar coolness.

“…Yes,” Haruka inclined their head, already feeling the pull of the water shining pink from the inflated plastic and yellow from the overhead light. “This is fine.”

“Great,” Rin shuffled his arms a touch, and sucked in a sharp breath. “In y’go, then…”

The rump of Haruka’s tail first broke the water’s still surface, and the level rose with their weight as Rin softly, carefully submerged their body in the knee-deep pool. In the corner of his eye Rin spotted how their eyes glittered and rolled shut at the small, vitalising body of water, and he couldn’t help his snort.

“You really like the water, huh?” he teased, chuckling some more at how Haruka only nodded in a languid bliss.

 

“The water is alive,” they all but purred. “It calls to me…”

 

“Oh…” Rin’s eyes went round before he averted them, awkwardly tousling his hair. The low, honeyed tones of Haruka’s voice tickled the pit of his abdomen, making him gulp. “I guess that’d be, uh, normal. For a siren…”

Haruka laid their head on the squishy plastic of the pool, staring at the slow crawl of the ceiling fan. “…Maybe.”

Rin quickly licked his dry lips, still crouching as he rested on the balls of his feet, crossing his arms over his knees. He mentally patted himself on the back for making the bandaging waterproof, and pulled away so he could watch Haruka enjoy themself in their element more clearly.

“...What do you mean maybe?” he asked softly, watching water collect in the dip of Haruka’s collarbone.

Their neck turned to meet Rin’s gaze, holding it as their chest rolled in a soft chuckle.

“You sound concerned,” Haruka remarked. A corner of their lip pulled up. “Why is that?”

 

At the onslaught of their hushed laugh and subdued smile, Rin blinked rapidly.

 

“I…I don’t…know—” Rin’s words died into a wisp, when he felt a cool, wet thumb padding his swollen bottom lip. His mouth parted in a gape as he felt the dry skin go alight, his eyes growing to a painful size as he felt his body flush from tingling scalp to bursting toes. “H…Haru…? Wh- _What_ —” His eyes were frantic over Haruka’s untroubled, close face, but he was rooted to the spot. “What are you doing?”

Their eyes lidded, the blues almost shrouded beneath their silky lashes. “…Did you forget the ‘ka’ in my name?”

Rin stared dumbly, heart throbbing in his very body as they leaned closer, their sapphires for eyes scouring his heating face.

“N-No, I—” he gulped. A pathetic whimper nearly left his shuddering lip, when they brought their damp palm to his nape. “It’s just—Haruka’s a girl’s name, here, I mean—it just came out as—”

“Girls, boys…Sirens do not have those.” A ghost of a chortle left Haruka’s lips to brush against Rin’s, his skin flaring with goosebumps in his bodily shiver. They pressed their cool forehead to his sweating, and gave a slight, enchanting smile again. “Just call me Haruka…”

“O…Okay…” Rin drew in a deep breath, feeling so, so dizzy. “Haruka…”

“Your lip…” Haruka brushed their thumb down the thin flesh, bruised with their acquisition. “It looks painful.”

“I-It’s okay,” Rin swallowed his stammer, feeling the webs of Haruka’s fingers in the clutch of his neck. “It doesn’t hurt anym— _mn_ —”

 

Haruka drew their slim, warm tongue over his lip, and his eyes blew wide.

 

“ _Mm_ …”

A trembling, sweeping heat coursed through Rin’s body as they hummed, massaging the hypersensitive bruise with their lips. Rin couldn’t even think of moving any frozen muscle, before they pulled away with a faint, sensual smack.

“…There,” Haruka sighed, both hands now soothing Rin’s buzzing, slack jaw. “It should heal in a moment, now.”

Rin didn’t even blink. He didn’t even breathe. He only swallowed very, very deeply.

_Oh, fuck._

“I’m…I’m gonna…”

Haruka’s eyes fluttered, half-lidding. “Yes, Rin?”

A roaring, bellowing fire pushed at his gut, and a sheer need _gripped_ him—to ravish the heat out of his body, the sense out of Haruka, sucking and marking every pale nook and cranny of their soft, sculpted body.

 

—And that’s exactly when he fell on his ass.

 

“ _Rin_?” they grabbed the lip of the pool, looking over with sudden dismay. “Are you okay?”

“— _I’m fine!_ ” Rin scrambled up to his feet, his heart still pounding. “I’m fine, I’m fine. I gotta—I gotta shower,” he rambled, panting with a desperate flush on his cheeks. “I’ll make dinner, soon, I…— _shit_ , I’m gonna go—I really gotta—”

He practically sprinted for the bathroom, and Haruka blinked after a slam and click of a lock. Processing Rin’s agitation, they heard the muffled shout of another swear word.

The living room fell silent again.

Water sloshed as Haruka turned back their body, and laid in the sizeable pool. They stared at the ceiling fan again, and exhaled in their siren tongue.

 

“ ** _…I can still lure him, then…_** ”

**Notes for the Chapter:**

> ~~(will add notes in 20 min brb) lol i added in all the spacing just now ;D;~~
> 
>  
> 
> i just stayed at school to finish this chapter up and slapped the text on here—no spacing or typo checking or anything 8D and thinking of titles for each chapter would probably be a dumb move (see fig. 1: title of this fic)
> 
> oH and, in case you noticed and are curious, i'm using they/them for haru here. i feel like they're not really male in this au, and that sirens don't have distinguishers like that in general :p sometimes i accidentally use he/his out of habit though, so i hope i took care of that when i looked over it before posting!
> 
> now let's see where all this stuff heads :)


	3. Chapter 3

**Summary for the Chapter:**

> The officer tries to set some ground rules for the siren.

Rin grimaced in the mirror, tracing the definitely fading blotch at his lip where Haruka had licked. His other hand pressed the lip of the sink, and he narrowed his eyes down at his blood-stained shins.

“ _Shit_.”

He ran his fingers through his knotted, red hair with a strained sigh. After stepping inside the shower stall, he twisted open the faucet, letting the water turn hot as he tugged off his hairband so his hair fanned across his sweating nape. He made short work of peeling off his clothes, crusted with sand and sea, and the surrounding glass started to blur with steam. Water started trickling then gushing down, washing the cold sweat and dried blood off in rivulets down his body.

While Rin lathered his hair with cherry blossom shampoo, he began to think.

He supposed he’d just have to make dinner for two now. Ask what a siren’s typical meal would be besides human flesh, and then try to accommodate with the spartan insides of his fridge.

His red locks thickened to maroon under the shower flow, and he pumped some body soap into his palm.

Haruka had rendered him utterly useless. They were like a siren and incubus rolled into one; some hypnotic sex demon that spent their days in water and would probably haunt him in his dreams. Their face alone could make him reconsider total submission at the hands of death by consumption, and their voice nearly got his face chewed off. Added with their _touch_ , and…

 

_Haruka drew their slim, warm tongue over his lip, and his eyes blew wide._

 

He reddened at how heat pooled in his belly, grumbling as he grabbed his razor and shaving cream.

“What a fuckin’ weird day…”

* * *

Haruka sunk into the pool, deep in thought even though their gills felt a touch stifled. Water dragged down their hair, on their skin when they broke the surface. It spilled down their lip and into the pool again.

_It is fun to watch Rin._

“…Yes,” Haruka decided to themself. They lightly shook the water out of their eyes.

* * *

“Crap,” Rin’s brows pinched, and he angled his head further into the cupboard. “S’it in the hamper…?”

Rin was starting to feel chilly just a towel slung around his waist, but his sweatpants were nowhere to be found. And to get his sweatpants, he’d had to go to the laundry room past the kitchen, which meant…

He heatedly readjusted his towel, scowling. “You gotta be _shitting_ me…”

* * *

Before Haruka could say something immediate, a flurry of words appeared in their head—names of chest muscles, which even bulged with their strength, and a towel when Rin came out of the hallway. With how many there were, Haruka wondered if Rin was much stronger than themself.

“…Hello Ri—”

“Shut up, I’m just getting some pants,” he snapped, storming into the kitchen door while Haruka blinked.

They stared after the fading slaps of his footsteps. They idly wondered how Rin’s cheeks were so red when he seemed quite angry, and so pondered while enjoying the cool water.

Then they heard stomping again.

“Alright, _you_ ,” Rin came back into the living room. He was clothed this time, though Haruka enjoyed learning that the particular shirt Rin was wearing was called a muscle tee. “We’re gonna set some ground rules.”

Haruka listened to this, still thinking that he was fun to watch. They tilted their head. “Ground rules?”

“Yeah. Know what that means?”

They looked back to the water. “Yes.”

“Look at me,” Rin said, tone commanding. When Haruka obliged, directing their silvery-blue eyes up, they found his face very red again. “O-Okay, maybe not. Just—listen up, alright?”

“Alright.” Haruka still stared at him.

“Alright…” Rin’s mouth opened half-wide, before it clamped again. He wiped the sudden sweat of his palms on the side of his pants, and started again. “Okay, ground rules. One, no…hypnosis.”

Haruka’s brow furrowed. “What do you mean?”

“What I mean is I don’t want you to… _lure_ me, kinda,” Rin rolled his hands, missing how Haruka’s tail stiffened in the water. “Like, make me all dizzy and stuff, so you can… _eat_ me.”

“…That,” their lips thinned. They looked away. “Is difficult.”

“Wha—?” Rin’s teeth clicked in a gnash, frustration pinching his brow. His words came rough with disbelief. “I’m asking you to not try and _eat_ me, what’s so fuckin’ difficult about—?”

“You did not ask that.”

Rin blinked, suddenly unsure of whether to be annoyed or confused, and decided to go for both. “Huh?”

“You did not ask that,” Haruka repeated. At seeing Rin’s waiting uncertainty, they sighed. “You asked me to not lure you. I cannot help that.”

The sounds of the living room receded into the gentle sloshes of the pool water. Rin spotted how they studied the translucent webs of their fingers, and a new irritation pursed his lip.

“I still don’t get what you mean, y’know,” he informed dryly, hands set on hips. “Care to enlighten me?”

Haruka shot him a piqued look. “A siren chooses their lure like a human chooses their face. I cannot control how you react to it.”

“…Huh?”

“I can make my lure stronger,” they kept explaining, and rolled over in the shark-plastered pool. “But I cannot stop you from being attracted to me.”

A high blush rolled over Rin’s face, and his head whipped aside in a scoff.

“W- _Well_ , I—” Rin’s lips tugged down in a pained grimace. He nearly growled in his self-consciousness, before he looked back at them with renewed resolve. “Okay, fine.”

“You were not fine with it a moment ago.” Haruka squinted.

“Yeah, no, lemme finish,” he ran his fingers through his hair, thinking. “…Alright. Ground rules,” he repeated, and before Haruka could roll their eyes he pointed down at them. “If I’m being… _lured_ , then you gotta snap me out of it.”

“Snap you—?”

“ _Not literally_ ,” Rin tacked on in exasperation, running a palm down his face. “If it looks like I’m glad I’m losing it, just…splash some water on me, slap my cheek a bit, something,” he clarified, starting to rub his nape. “All I’m asking is that you try not to hurt me, okay? I wanna actually help you here, and me losing it ’cause of your lure—”

“I said I cannot help your attraction—”

“ _Your lure_.”

They cocked a brow. “…Stop interrupting me.”

“Stop interruptin’ _me_ ,” Rin retorted, a desperate sort of chuckle coming loose from how ridiculous the situation was. “Anyway, you get the point, right?”

“Right.”

“Good, that’s good,” he nodded. He pulled up the side of his hair, and blinked aside. “…Right. Next. No… _No_ kissing.”

Haruka sulked. “Why?”

“—Shit, you can’t ask _why_ ,” Rin clawed his scalp, fisting the locks as his lip tightened in a wince. “J-Just, could you not? _Please_?”

“I did not kiss you, though,” Haruka replied, cocking their head. “I healed your lip.”

At Haruka’s clear enunciation of the word ‘ _lip_ ’, Rin swore he could feel the hot stripe of their tongue on his mouth again.

“T-True…” he cleared his throat, and blinked up at the ceiling. “Thanks for that, I guess.”

They nodded. “Is it better now?”

“—Yes.”

“Oh,” Haruka paused. Their head tipped up curiously. “Can I see?”

“Jeez, honestly—” Rin looked down, scowl weakened by his impressively pink cheeks. “ _See_? Better.”

Haruka took in his distant behaviour. Their eyes cast aside.

“…You said you did not scare easily.”

Rin blinked rapidly. “Wha—? Yeah, but—”

“We already agreed I would not hurt you,” they mumbled. “You do not have to be afraid.”

Rin chewed his lip. He swore their voice tinged with hurt, of all things.

“…Yeah…” he exhaled through his nose, “Yeah, you’re right. You’re not like a ticking time bomb or whatever.”

Haruka nodded, agreeing. “Yes. I am a siren.”

“Gotta work on those similes, huh?” Rin jutted his chin in a chuckle, before he knuckled his jaw in earnest. “But yeah, what else is there that I oughta make clear—?”

A shrill sound rang out, startling Haruka.

“What is that?” they jerked their head, and watched Rin head back into the hallway.

“S’just a phone call,” he looked over his shoulder to tell them, before disappearing fully from their sight. “I’ll be back in a sec.”

Haruka realised it was an abbreviation for second. They promptly counted.

“…That was a lie,” they mumbled, before turning back to watch the ceiling fan again. _How confusing._

They closed their eyes, and listened to Rin’s voice after the ringing stopped.

“Hello, Matsuoka Rin spea—… _oh_ , Sousuke! What’s up?”

Haruka frowned at the ensuing chatter, still closing their eyes. This time, however, they weren’t confused by how Rin seemed to be speaking with someone that didn’t seem to be in the apartment.

“Matsuoka…” they murmured to themself, brow knitted as their eyes fluttering open. “…I have heard that before…”

_But when?_

They found themself stuck on the question. After the few minutes of Rin’s call, after the list of rules that they mostly paid attention to, and even when Rin went to prepare their favourite food (which was called mackerel, a strange name) Haruka still found themself firmly rooted in the passing question, a pressing realisation.

_I have heard that name before._

**Notes for the Chapter:**

> Stayed up to finish off this meagre chapter; i got a fic planner now so more advancing stuff should come by the next one :)


End file.
